Add a new workflow for release branch processing

[NikitaSkrynnik]

Issue

#11430

Description

This PR presents a new release workflow for deployments-k8s. It works the following way: cmd-repos create release/networkservicemesh/*: ${TAG} branches with updated images. This workflow starts on every push to any of release/networkservicemesh/*:${TAG} branches.

The workflow does next steps:

1. Get all release/networkservicemesh/*:${TAG} from deployments-k8s and compare them to a set of images from app folder
2. Check If the set of branches is equal to the set of images. If the sets are not equal then exit else continue
3. Create release/${TAG} branch
4. Merge all release/networkservicemesh/*:${TAG} branches into release/${TAG}
5. Push release/${TAG} branch to remote deployments-k8s
6. Delete all release/networkservicemesh/*:${TAG} branches from remote deployments-k8s

How Has This Been Tested?

• Added unit testing to cover
• Tested manually
• Tested by integration testing
• Have not tested

Types of changes

• Bug fix
• New functionality
• Documentation
• Refactoring
• CI

[denis-tingaikin]

I like the idea of avoiding creating PRs from the NSMBot on release.

The workflow file can be simplified.